When user plane congestion occurs in a wireless communication system including a wireless transmit/receive unit (WTRU) and a network, (for example, a radio access network (RAN) or a core network (CN)), the congestion may be detected and reduced by applying a congestion control mechanism based on a per user basis, a per application basis, or a per content user basis. A per user congestion control mechanism may reduce the traffic of the users of lower quality of service (QoS) assurance to alleviate the congestion, while maintaining the traffic rate of the users of higher QoS assurance. A per application congestion control mechanism may delay or drop the traffic of certain non-critical applications, such as file transfer protocol (FTP) downloading, social applications, and the like, to alleviate the congestion and reallocate the resource to more critical applications, such as a voice call. A per content type congestion control mechanism may subject a particular media type, which is more resource consuming but less important, such as video, to some control method, for example, compression or transcoding. The mechanisms described above may be used in combination.
There is currently no mechanism available for the system to classify certain subscribers as users that may have paid an extra premium such that a satisfactory level of service may still be enjoyed despite congestion. For example, the system may allow different levels of subscriptions, and each may have different implications to user experience when congestion occurs. Consequently, the system may not be able to revert back to normal services when congestion terminates. Nodes, such as evolved Node-Bs (eNBs), may be the only nodes involved in responding to congestion level changes. These nodes may not have the capability or functionality to modify their behavior in response to an indication from other parts of the system. Therefore, there may be a lack of congestion related information exchange between CN nodes, (for example, a mobility management entity (MME) or a packet data network (PDN) gateway (GW)), and the eNB.
Further, the network may not be able to inform a WTRU about congestion in the system, such that certain applications or traffic types may not be allowed, even though other types of applications, (for example, those that may not require high QoS resources), may be handled by the network. Currently, the network may inform the WTRU that it is congested, which may result in the WTRU failing to access the network for services that require minimal QoS. Moreover, the network may inform the WTRU to take certain actions or the mere indication from the network may lead the WTRU to execute certain procedures that may help reduce the congestion in the network. Such behavior may not be supported by the network.
In relation to WTRU-awareness of congestion, there is also no user awareness of network congestion. This may be desired as the user may prefer certain applications over others. Thus, the WTRU may reflect user preference to the network so that certain traffic may be allowed when sacrifices need to be made, (in the form of providing a limited QoS or supporting a subset of applications only).